Aquatic Invasions (2009) Volume 4, Issue 4: 675-680
DOI 10.3391/ai.2009.4.4.13
© 2009 The Author(s)
Journal compilation © 2009 REABIC (http://www.reabic.net)
This is an Open Access article
Short communication
First records of Mnemiopsis leidyi (Ctenophora) from the Ligurian,
Thyrrhenian and Ionian Seas (Western Mediterranean) and first record
of Phyllorhiza punctata (Cnidaria) from the Western Mediterranean
Ferdinando Boero 1* , Marco Putti 2 , Egidio Trainito 3 , Emanuele Prontera 1 , Stefano Piraino 1
and Tamara A. Shiganova 4
1
DiSTeBA, CoNISMa, CMCC, University of Salento, 73100 Lecce, Italy
Ufficio Ambiente, Comune di Lerici, Piazza Bacigalupi 9, 19032 Lerici, Italy
3
Villaggio i Fari, 07020 Porto San Paolo (OT), Italy
4
P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, 36 Nakhimovsky Av., Moscow, Russian Federation
E-mail: boero@unisalento.it (FB), marcoputti@comune.lerici.sp.it (MP), et@egidiotrainito.it (ET), lele.prontera@libero.it (EP),
stefano.piraino@unisalento.it (SP), shiganov@ocean.ru (TAS)
*
Corresponding author
2
Received 26 October 2009; accepted in revised form 20 November 2009; published online 2 December 2009
Abstract
The gelatinous macroplankters Mnemiopsis leidyi and Phyllorhiza punctata are recorded for the first time from the Italian coasts
of the Western Mediterranean. In the framework of the CIESM Jellywatch campaign in the summer of 2009, M. leidyi was
recorded from the Ligurian, Tyrrhenian, and Ionian Seas, including swarming episodes that, together with those reported from
Spain in the same period, suggest a great success of the species in the Western Mediterranean. A single specimen of P. punctata
has been recorded from Sardinia. These species do not sting or harm humans and no impact on tourism is expected, but they
might harm fisheries by predating on fish eggs and larvae and their prey, zooplankton. The large distribution area of M. leidyi
suggests that the species invaded the Western Mediterranean during the summer of 2009, but its establishment is still uncertain,
since the populations might not withstand winter conditions. The isolated record of P. punctata just indicates that it can reach
this part of the Mediterranean.
Key words: non-indigenous species; gelatinous plankton; citizen science
Gelatinous plankton outbreaks, often considered
as freak events in plankton ecology, with sudden,
short-lasting and unpredictable effects, are
increasingly frequent at a global scale (CIESM
2001; Boero et al. 2008a). Besides the increase
in the abundances of native species (e.g. frequent
swarms of the scyphozoan Pelagia noctiluca
(Forsskål, 1775)), gelatinous plankters are also
represented by non-indigenous species (NIS) and
are increasingly reported as aliens. The highly
invasive ctenophore Mnemiopsis leidyi A.
Agassiz, 1865 is probably the best example of a
gelatinous invasive NIS. Shiganova et al. (2001)
reported on the intense effects of M. leidyi on the
ecology of the Black Sea, recording its presence
in the Eastern Mediterranean close to the straits
connected with the Black Sea. Shiganova and
Malej (2009) found M. leidyi, in 2005, in the
Gulf of Trieste, the coldest part of the
Mediterranean basin, and also referred about the
finding of few individuals near Marseille (French
coast of the Western Mediterranean) in 2005. In
the summer of 2009, Fuentes et al. (2009)
reported swarms of M. leidyi along the Catalan
coast of Spain (Western Mediterranean). In the
same period, the species was also recorded by
Galil et al. (2009a) from the coasts of Israel, the
warmest part of the Eastern Mediterranean. In
the same area, Galil et al. (2009b) found the
tropical scyphomedusa Phyllorhiza punctata
Lendenfeld, 1884, already recorded from the
Eastern Mediterranean in the past, but absent for
many years. These records, together with the
expansion of the scyphozoan Cassiopea
andromeda (Forsskål, 1775) (Cevic et al. 2006)
and of the hydrozoan Clytia hummelincki
(Leloup, 1935) (Gravili et al. 2008), show that
the biodiversity of the Mediterranean Sea is
being characterized also by the establishment of
gelatinous warm-water NIS. Gelatinous macro-
675
F. Boero et al.
plankters, albeit very evident to casual observers,
are rarely reported in traditional plankton studies
since, when abundant, they clog plankton nets,
and are not observed from satellites. As a
consequence, both the traditional (nets) and the
modern (satellites) ways to study plankton
frequently underestimate gelatinous plankters.
Blue diving and submersibles are the preferred
methods to study their presence (Mills 1995), but
do nonetheless require intense observation
efforts that make large scale evaluations
difficult. In spite of repeated claims that our
oceans are shifting from fish to jellyfish (see
Mills 1995; Boero et al. 2008a for reviews),
records of gelatinous swarms are usually
scattered and the perceived global trend derives
more from the collation of disconnected records
rather than from a coordinated, large scale
appreciation of the phenomenon. When the
ctenophore Mnemiopsis leyidi suddenly appeared
in the Black Sea, developed enormous
populations and affected the total ecosystem and
fish stocks, the evidence of the importance of
gelatinous plankton in marine ecology became
overwhelming. From the Black Sea, the invasive
ctenophore spread to the Sea of Azov, Marmara
and the Aegean Sea. It was also brought into the
Caspian Sea, where it strongly affected all
ecosystems, with the exception of the Aegean
Sea, where it did not create a reproductive
population due to oligotrophic conditions
(Shiganova 1993; Shiganova et al. 2001, 2004).
To acquire a more precise picture of the
occurrence of gelatinous plankton aggregations,
the Mediterranean Commission (CIESM),
launched a citizen science initiative, the
Jellywatch Programme, in the summer of 2009.
Citizen science is becoming a common practice,
especially to record the presence of species that
are not easily recorded by traditional methods
(Silvertown 2009), such as gelatinous plankters.
The pilot phase took place in Italian waters. A
poster with the main gelatinous plankters of the
Mediterranean Sea was distributed nationwide
(Figure 1) with great media coverage helped by
the environmentalist association “Marevivo”
(http://www.marevivo.it). The 8000 km of the
Italian coastline are intensively frequented by
tourists throughout the summer and these
citizens, together with beach authorities and the
Coast Guard, provided hundreds of records of
gelatinous plankters. Records were often
documented by pictures and were assembled in a
database. All the species present in the poster
676
Figure 1. The Poster of the CIESM Jellywatch Campaign (Art
by Alberto Gennari, Graphics by Fabio Tresca, Map by
Giuseppe Guarnieri) (Translated from the Italian version used
during the campaign)
were reported, with the exception of Rhopilema
nomadica (Galil, 1990),which so far has only
been reported in the Eastern Mediterranean
basin.
Records of Mnemiopsis leidyi. The first
records of M. leidyi were made offshore, from
boats in the Ligurian Sea, in May 2009, but no
pictures were provided. Being the first known
records of the species in this part of the Western
Mediterranean,
these
observations
were
considered as dubious due to lack of proper
documentation. In June 2009, a swarm of
M. leidyi in the Ligurian Eastern Riviera was
photographed
repeatedly.
The
organisms
(Figures 2A, B) were clearly identifiable as
M. leidyi. The species was present in that area
continuously throughout the summer, until its
decline. When the swarms started to dissolve,
numerous specimens of the fish Sarpa salpa (L.,
1758) were seen to feed upon the spent
ctenophores (Figure 2C). The complete list of
Mnemiopsis leidyi and Phylloriza punctata in W. Mediterranean
Figure 3. Map of the Italian coast with all locations where
Mnemiopsis leidyi was recorded (red dots) during the summer
of 2009 (for details see Table 1). Phyllorhiza punctata
wasrecorded from Tavolara Island (yellow dot)
Figure 2. A swarm of Mnemiopsis leidyi from the Ligurian
Sea (A), M. leidyi from the same locality (B), fish (Sarpa
salpa) prey upon spent M. leidyi (C) (Photos by Marco Putti)
sightings (occasionally backed up by photographs) is reported in Table 1 (see also Figure 3).
Record of Phyllorhiza punctata. A specimen
of P. punctata was photographed at the sea
surface inside the Marine Protected Area of
Tavolara, at Cala Suaraccia, Sardinia on October
1st 2009 (Figures 3, 4). The jellyfish umbrella
measured 35 cm in diameter. It was not
collected. This is the first record of this species
from Italian waters and from the Western
Mediterranean.
Figure 4. Phyllorhiza punctata. Photographed from the
surface at Tavolara Island, Sardinia (Photo by A. Severino)
677
F. Boero et al.
Table 1. Records of Mnemiopsis leidyi along the Italian coasts during the summer 2009, deriving from the CIESM Jellywatch
Geographic coordinates
Latitude, N
Longitude, E
Survey date
(in 2009)
offshore Genova
44°20'01.25"
8°54'23.95"
May 03
offshore Genova
43°41'29.38"
8°58'34.04"
June18-19
Fiascherino, Lerici
44°03'25.00"
44°03'44.12"
9°55'54.88"
9°55'23.64"
May 20
July 29
Recco
44°21'21.96"
9°08'30.65"
Marinella di San Terenzo
44°04'56.60"
44°04'56.60"
44°04'53.14"
44°04'53.14"
Ponza island
Tellaro, Lerici
Estimated abundance
Photo
3 specimens
No
scattered specimens
No
<10 specimens
patches of 10-20 specimens
Yes
Yes
June 26
5 specimens
No
9°53'40.43"
9°53'40.43"
9°53'25.82"
9°53'25.82"
July 05
July 28
July 31
Sept 01
thousands
thousands
>10 specimens
>10 specimens
Yes
Yes
Yes
Yes
40°53'37.69"
12°58'02.29"
July 13
thick patches
No
44°03'29.94"
9°55'42.76"
July 27
thousands
Yes
Eolie islands
38°29'33.85"
14°54'26.71"
Aug 01
1 specimen
No
Nervi
44°22'50.46"
9°01'49.79"
Aug 01
2 specimens
No
Punta Falcone, Piombino
42°55'54.91"
10°29'47.61"
Aug 01
6 specimens
No
Baia Blu La Spezia
44°04'58.47"
9°53'12.80"
Aug 02
thick patches
No
Petrosino
37°42'32.00"
12°30'04.02"
Aug 06
scattered specimens
No
Quercianella
43°27'33.50"
10°22'09.43"
Aug 22
patches
No
Rocchette
42°42'58.00"
10°57'38.26"
Aug 23
patches
No
Isola di capo Rizzuto
38°54'33.26"
17°01'26.67"
Sept 06
1 specimen
No
Location
Talamone
42°33'22.67"
11°07'17.67"
Sept 08
<10 specimens
Yes
Formiche di Grosseto
42°34'60.00"
10°52'60.00"
Antignano
43°25'36.42"
10°19'17.45"
Argentario
42°26'20.38"
11°07'26.13"
Calafuria
43°28'21.54"
10°20'25.74"
Sept 09
Sept 09
Sept 10
Sept 10
Sept 13
Oct 04
<10 specimens
1 specimen
1 specimen
<10 specimens
patches of 10-20 specimens
2 specimens
Yes
No
No
Yes
No
No
Citizen science is an effective tool for
monitoring gelatinous macroplankton. Many
observations reported here, in fact, were not
made by professional scientists, but stem from
lay individuals that were aware of the Jellywatch
campaign and made their reports accordingly.
The CIESM Jellywatch, furthermore, increased
attention towards gelatinous plankton, so leading
to records of species that were not even covered
by the campaign, such as P. punctata.
The distribution of professional researchers
along the thousands of km of the Mediterranean
coast is insufficient to effect a proper coverage
of the entire area, whereas lay persons can
provide information that otherwise would be
lost. Scientific surveys, entailing the employment of scientists and oceanographic vessels,
would be expensive and inefficient, considering
the erratic occurrence of gelatinous plankton.
678
The records from the Catalan coast (Fuentes et
al. 2009), coupled with the present ones, demonstrate that, during the summer 2009, M. leidyi
was present along the northwestern coast of the
Mediterranean. It is improbable, as suggested
also by Fuentes et al. (2009), that the species
reached all these places through human
intervention, e.g. by transport in ballast tanks.
The spread of the species outside the Black Sea,
(Shiganova et al. 2001; Galil et al. 2009a) and
the present records, show that M. leidyi is
present throughout the Mediterranean, from the
coldest (Gulf of Trieste, Italy) to the warmest
(Israel) areas of the basin. Experimental data
have shown that the conditions of the Aegean
Sea can be well tolerated by M. leidyi. It can
live, feed at a high intensity, and reproduce
there. Its eggs develop well, with high percent
survival and development (99.7%). The only
Mnemiopsis leidyi and Phylloriza punctata in W. Mediterranean
factor which limited creation of semireproductive population was very low prey
(zooplankton) density under the oligotrophic
conditions of the Aegean Sea (Shiganova et al.
2004). The present outbreaks of Mnemiopsis at
several locations of the eastern and western
Mediterranean might be the result of changes in
the conditions of these coastal areas. This
hypothesis is supported by increasing blooms of
native jellyfish species, probably favoured by the
release of jellyfish from fish predation and or
competition due to overfishing (Boero et al.
2008a). It is unclear whether the Western
Mediterranean population will survive yearround, but its bloom, as well as the presence of
P. punctata, are causes of great concern for the
state of Mediterranean ecosystems.
Mnemiopsis leidyi formed swarms in the
Western Mediterranean (Figure 2A) during the
summer but, at the end of the favorable season,
the species was preyed upon by fish like Sarpa
salpa (Figure 2C). Predation by fish, however,
occurred only in the final phase of the blooms,
when the individuals were spent.
The record of P. punctata, albeit isolated,
suggests that the conditions of the Mediterranean
Sea are more and more conducive to the spread
of species of warm water affinity. The records by
Galil et al. (2009b) demonstrate that the species
is present in substantial numbers in the
Levantine Basin. The present record shows it can
spread to the Western Mediterranean. Lotan et
al. (1994) suggested that the tropical
R. nomadica, highly invasive in the Levantine
Basin, will not reach the western Mediterranean
due to intolerance of lower temperatures. In spite
of having been covered by the Jellywatch poster
(Figure 1), R. nomadica was not recorded in the
present study; despite a high presence in the
Levantine basin, it has not yet been recorded in
the western basin, even though climate warming
might be conducive to future westward
expansions of such warm-water NIS (see Boero
et al. 2008b for a review).
Mnemiopsis leidyi and P. punctata have
severely impacted fisheries in the Black Sea
(CIESM 2001) and in the Gulf of Mexico
(Johnson et al. 2005) respectively. Not being
stingers, however, they should have no negative
impacts on tourism and human health.
The connection between the presence of
gelatinous macroplanktonic NIS and a decrease
in fisheries yields is difficult to quantify. The
impact of gelatinous plankton on fish recruitment
has long been documented and has been
highlighted by jellyfish scientists (e.g. Purcell
1989; Mills 1995; Shiganova and Bulgakova
2000; CIESM 2001; Boero and Bonsdorff 2007;
Boero et al. 2008a), but only very recently have
fisheries scientists begun to introduce it in
ecosystem models (Coll et al. 2008; Pauly et al.
2009). This recent conversion, also linked to the
enforcement of the ecosystem approach to
fisheries (Boero 2009), justifies the call for
jellyfish inclusion in future fisheries models.
Acknowledgements
The Mediterranean Commission (Commission
Internationale pour l’Exploration Scientifique de
la Mer Méditerranée: CIESM) provided precious
advice, support, and resources to produce the
poster of the Jellywatch. The Environmentalist
Association Marevivo helped in spreading the
information about the Jellywatch and collected
records from its associates. This work is part of
the activities of F. Boero, S. Piraino and T.
Shiganova within the EU projects SESAME and
MarBEF, and the Italy-Israel Cooperation
Programme on Environment Research and
Development, funded by Italian Ministry of
Environment and Territory. CoNISMa and
CMCC provided infra-structure and support.
Maps were based on Google Earth. Andrea Gerli,
Leonardo Martini, Michele Isman, Giulia
Bernardi, Paolo Maria Politi, Elisiana Cozzani,
Maria Angela Bari, Salvio Foglia, Camille
Marquand provided records of M. leidyi. Andrea
Severino photo-graphed P. punctata. Bella Galil
helped in reviewing the manuscript.
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